1. Field of the Invention
The present invention relates generally to physical markers located on optical discs. More particularly, the present invention is directed to using physical markers to provide synchronization during acquisition of data from optical discs.
2. Description of Related Art
Recent developments in optical disc design, optical disc manufacture, and in the design and manufacture of drives for reading these discs have now made it possible to use optical disc drives to interrogate disc surfaces for the presence of nonoperational structures.
As described more fully in copending and commonly owned U.S. patent application Ser. No. 09/183,842 filed Oct. 30, 1998, 09/311,329 filed May 14, 1999, and 60/134,368 filed May 14, 1999, hereby incorporated by reference in their entireties, these nonoperational structures produce signals during trackable reading that are discriminably embedded within the normal electrical responses; the embedded signals report physical properties of the nonoperational structures. In conjunction with analysis software newly developed for this purpose and described more fully in “Methods And Apparatus For Analyzing Nonoperational Data Acquired From Optical Discs,” Worthington et al., U.S. patent application Ser. No. 09/378,878 filed on Aug. 23, 1999, hereby incorporated herein by reference in its entirety, permits these signals to be characterized, classified, mapped, and represented visually.
In essence, these developments permit the disc drive to be used for scanning confocal laser microscopic inspection of one or more disc surfaces.
The robustness of this approach makes possible the optical inspection of structures having enormous variety in shape, size, and chemical and optical properties. This flexibility in turn permits such nonoperational structures to be used for a wide variety of signaling chores. For example, as described more fully in copending and commonly owned U.S. patent application Ser. No. 08/888,935 filed Jul. 7, 1997 and 09/120,049 filed Jul. 21, 1998, hereby incorporated by reference to their entireties, such nonoperational structures can be used to signal the results of chemical and biological assays, ranging from immunoassay, to enzymatic assays, to nucleic acid hybridization assays, to direct detection of mammalian cells.
In each of the laser microscopic applications of optical disc drives, though, the nonoperational signaling structures must be disposed upon or near a surface of the optical disc prior to reading. For some applications, it may suffice to dispose the nonoperational structures randomly upon the disc surface, as in certain simple counting applications. For other applications, such as in nucleic acid array analysis (see, e.g., WO 98/12559), it may instead be preferable to dispose these nonoperational signaling structures in one or more ordered arrays. In order to detect these structures, there exists a need in the art or methods, apparatus, and compositions that facilitate the acquisition of data from the optical disc.